Process for producing substituted hydroxy aromatic compounds



..a.lrea y ,p esent n m eiwsl i n iv ndsl e n n. e

azot etionha rd h drolysi -t.

spru e-S then-thatot the pestv Anoth r object. achieved b Patented July 15, 1952 elocates} Q PRODUCING sUBSTI'rUIrED 1. ,HYZDROXY AROMATIC. CO1!POUNDS:

rarfassienor to a i a burgh; Pa.,.a'=corporationof llelaware. v

No Drawingg' Appllcationj Serial No. 758,9

. 5 Claims. 1

This invention relates to a process for producing substituted hydroxy aromatic compounds and-more particularly to a process for producing hydroxy, aromatic compounds bearing a substitu e t in p a position on the nucleus other than {the tom which eld-he tak ii, q PWPbfifi' t n-i s" 1 6 well known that the. orientation of enterlips suhstitueiit. into the nucleus of an, aromatic ton poundv dep nds:

upon "the suhstituent groups the'Qa-romatic nucleus'. f1 he o a mma iomiq eus 8 .11 those which directthene gt enhose lro 'setlesh si twocliisses, 1.,

toting substitjentkto themetal-positionand wh c dirseisiiii is e er n u fii n o \ottho and/zor para positions, Substitutionin he para orienting influence and substitution 1 Toiiho end/ Pare ms iion o r o n s s t me a me o-e ie iin influ nce has ng ven mn she by emp o n a bl in r u 5! was stituti n in either the ortho or t f s an obj ct ach eved by this invention to P vide an wessio roducme ydroxy aromatic communes bearin a substi u n ;.in-;a position nwthernu eu t e than th positi n wh lwbu donqrmal y taken on, ireot;sub tit.ution according,,.to a ,simpler and more .economica1 y thisvinventionpis to. pro ide? a p o ss for producing :hydmxy 81'0- maticrco npoundsin'which asubstituent is placed at a redetermined abnormal :position ion the :oromaticznuoleus; 1 1 o V A :iurtherobjeot achieved by this invention: is pr vide. .8; process which yields essentially only one. isomer .of ;a. substituted 'hydroxyv aromatic compound to the substantial exclusion of other ,iso ners 1 which normally are formed von direct.

substitut on-u. a

lacoomnli'sh these .:and oti 1er ooJects; which will becomeapparent ago-the description-proceeds, by employing atertiaryalkylgroupi as a:b1ock- ,inxagent. I have found 'that ztertiaryl ia'lkyl groups: or ir'om 1112012, carhonratoms are particu- .larlmoesirahlo iorwthepurpose of my invention.

tertiary allcr l. rou s m y be ea ily added 2 9 an aromatiohucleusowe oonl nnds w conditions-mam they; be a aqil r m ve r the :desired "s bstitution; has; teken zn eoerw or disturbing, oth r .rsubs f uenta 0 th ie-tic qnucleus.-: Acriticaliactor-w th sp t horro moval of a tertiary alkyl group from anarornatic nucleus-without affecting other huclepssubstituents-is;thatrthe aromatic nucleus musticonta n a hydroxyiradicalr H F Inacdordance :with my invention; the, tort my ,alkylgroup or- -groups aused for blocking mus be oriented alkyl groups, e., the. tertiary; ....:il l :g'roups mu'stloocupy at least one ofthe. positi n to which an entering substituent would, be directed if the tertiary alkyl group were not blocking that position. oriented tertiary alkyl group then is one wh h occupies a definite spatial" position relative o" some other gropp'or some other part of the; aromaticnucleus'. The (oriented tertiary'alkyl,group" as used herein may-therefore be defined asa tert "rfy allgyl group which ispresent on"-the:1fii 'g position dictated by the orienting forces Qf fthe funalkylated "compound. For example, in, "the a t t qn 2 aimeta di t n om und B ck e nitrobenjzen'e with iisobutylene, a tertiary" butyl group would enter the meta position thusio'rinn sta-n t es iarv t benzen r. t eas th ter iary' ty g ou w u d .ocoupy h orientegiff position with respectto thefnitro group 'wi the otherhandif t ertiaigy butyl ri- .nitrqsr ub' wou d f "rient'ed' tertian alkyl group.imetagnit' tiarvbutmbenzene ont i orient d f'e'nzer'ie juices filkylgrou -"f r jiln b rief, the process of myinventiofri inclu 's "lthefisiieps of lalkylating an iai omaticlcomp d capable oirexeritin'g a 'rective infiuenc" firstllent "hgiie't af alkyl' .the 'i1,i.l,cleus of, her" V to p undja d s ed' u s i lent; and Ithe oaikyla ing riei u s itutea a kt'la 'ediaromati q to g ve a substituted aromatic}. I

T e n -un process of. inventionth ialkylat' n, be omitted in certainiris cesr ,Eo ekaniple ma be; u -ala Jib? ;c leus followed l-by :dealkylatiom to: rem-ove the mer- .tiaryialltyl .groupiorzg'roupsiiwhich were; originally su tabl ails atedams at c r o e eu idsare-ave =By="-"an aromatic-compound apable Of exert- Where, an hydroxyl; radic T: i 2,603,662 i:

present. If, however, a suitably alkylated aroa methylation, hydrolysis, and deputylation as illusmatic compoundgisnot availiaible, itjmay be preft area; by; Equation k-helvuf ,If} toluene is pared according 'to 'any"meanskncwn'inthe" art, "chosen as the starting"'material for thepreparasuch as alkylation, rearrangement of a tertiary tion of o-cresol my'process may comprise the alkyl aryl ether, etc. For the purpose of illus- 6' steps of butylation, chlorination, hydrolysis, and tration of my invention I will hereinafter describe debut'ylation-as-illustrated by Equation VI below. the first step as an alkylation: step. Thus, the, i- A'cccrdi'n'g to a preferred embodiment of my process of my invention comprises either prepar.- invention; 1 -;use phenol or a substituted phenol ing or selecting a tertiary-alkylategi. aromatic V as a,.starting;materiall However, I may use other compound and treating this compound-toiorm a; 10. substituted 7. benzenes as represented by the substituted derivative, such that on removal of. formula,:,

one or more of the tertiary alkyl groups there I l sulting compound will have substituents placed in relation to one another in a manner abnormal I to that which would result from direct substitution -in the unallrylated parent compound, or such tft cn'removalicfz'onebrmore'of the-tertiary i c sfl ns e sq ri a ma e m- -where Yisone of the substi 'ents as-listed bcve. i nd b a fl t substantlal Furthermore;- more tliaiithe substitii'iit'nia be q -s i m 'w m d- 2 present onthe aromaticmucleiis provided t t -obtainedbydirectsubstitution in the unalkylated g least 'tWbC Q bhfDb t dhE into one pai t p 1 j of which anentering substituent will be oriented.

land. other u s it te f mi P 1 h? j same-11s ceral character} 7 t will hefrecogriiae dthat the,abovelist;does fnot'includeall ofth'e'radicals whiclifexert a a v 40 recti'v'e influence n substitutionlreactions; This V The P T- am Step. pi 11m; process comprises :listfis given bv wayioi.eiamiiie only anus-not i t??? i ix r l fi 191 7 9 ena e" .Q "intendedto mposeaiiy limitations an the scope 'f l s' dlrectlve WF iuPQ I fi ribr-jthis 'inventidm; -51 1 mg flvtl alk l oup- The mber of ter ary i ,0,t1i r,a biiiatietom ouii capable or exerting FYl f p ,m lc yi th n q s'f i' fih ajdirectiveliniiuenceuponaivfirstentering ter- 45 m at FQ Pd'dPD S'uQOQ the} atureof 'tiaiy alkyl grciipl'are naph halene; insane, anhe-fi al p du s d- F rbxamplqinfthe Hthfa'cene, 'fiuor'eneIphenanthrene; and 'the like. PEP 'F V- n -d mo henol from jliheno'l. :stiu ther cqmlioufndscapable fofl j'er zertingfan Q t'lfipfim y' y-t bl ck-jt e posit fi jt ius orienting infiuencefuponenteringftertiaryfalkyl V lrl j9 -'tg r y -alm er0up.'- -In"the jgrdups u iit o't ie ciass or netrocycl sssuchas '5 'Preparatwn: tr9PP i f om frzh nql it raii, i'ophe efii t'ri'ma dump ne.1ndole.be riwould fib 9k 6-pq' ibi 'f =tionsthus'requiring three-tertiary alkyl-gro'ups;

Thearcmatic compoundsjwhich may, begus ti l f z Q jar m ct ma -be Tas starting'imatelials in accordance with the pros;- re i fl 'ec e i yq s i w h mammals- 'es's'bf this" invention fall' into three general '5 13' ag r qph a a a q efip containi classes, namely: (1) aromatic compounds conlzj P -ln0lecu1ein the presehde ';ta ining an hydroxyl radical, such as phenol, of smanQamounts f' d q si n a ht. cr esoli naphthol,"etc., and substituted derivatives 9 v 9 1 a es' mereiy' undeflhat' and 'bi'these; (2) aromatic compounds containing a pressure; other means o bbtainihg'thfllkylated a u t at em cbnvertible t an 60 ccmpoun'dimay be 'employed w'ifliolltdeviating jdroxyl radical, such as chlorobenzene, omand o the j t of $1115 n n lkyl pachlorotoluen e chloroxylene etc and aro- 1 connected t0 thearomatic Ilnatic compounds not containing an hydroxyl fi 8 3 9 S n I h e fo nd that' tertiary alkyl 'radical or a radical that can be directly converted g s f e yj i m t into an hydroxyl radical, such as toluene, xylene, 6 bthellisubstituentsi n the? arcmatic 'nucleus naphthalene, anthracene, etc. 'flThe procedural f fi 1a "9 i f r s cqnda alkyl Qs QDS 'lv aturallyawill va y depending upon the groups. 1 particular material chosen. 7 Examples 8 'W kyPgmups which "'lIi phenol is chosenas the-startingmat ri l o Fc we tettiary but, tertiary thb brepar'ationof 2,6-dich1biOPh n01 my p og 11 rl gbutyl, trnsobutyl; and the likes lnlacccrdance may comprise "the steps {of butylaticn, chlorinafwlth e e eii folmzofzmyinventionz-l emvtion; and debutylatibn asillustrate'd by Equaticn 1931 a? er iary butyl-1gr0lip i i v y below; If;h1orobe'nz en is chbseni as "the .easilyigemoved' 'to'form isobutylne whichicanbe starting material for? the. preparation of o-cresol -recoverediand used-tiagain for alkylatiori purposes. *myl'miocessimayicemprise the steps'of butylatio'n, 7'5 =Fu'rthern'iore; iisoloutyl'ene its'elt is inexpen'sive and is readily available-inrefinerygases-such as those resulting from cracking-operations.

When the substituent'addedin the second step of myinvention is an alkyl group, it is important to choose as an alkylatingmaterial"in'the first step a tertiary alk yl'group that is more easily removed than the alkyl group put on in the second step. Usually tertiary alkyl groups are more easily removed than primary or secondary groups. For example; ifja normal amyl radical is added to an aromatic nucleus in the second step of my invention, I prefer to employ trimethylethylene or isobutylene as my alkylating material in the-first step. Various condensin agents may be used in the alkylation step including aluminum chloride, zinc chloride, zirconium tetrachloride, ferric chloride, boron tri-fiuoride, phosphoric acid, sulfuric acid, activated clays and the like.

The second major step of my process comprises substituting on the aromatic nucleus in at least one of' the unoccupied positions of the alkylated aromatic compound produced in the first major step, an organic or inorganic radical depending upon the final product desired. Substitution is effected in a; conventional manner other metallo radicals, and the like. The replacement of hydrogen on the nucleus of an' aromaticcompound with a radical such as a halo, nitro, sulfo, and the like may be accomplished by a direct substitution. Substitution of certain radicals, however, may. require a more complex procedure. For example, the substitution of an hydroxyl radical onth'e' nucleus of an aromatic "cofr'np'oun'cl such as toluene may require two separate reactions as illustrated hereinbelow by Equations VI, VII, and VIII. "As exemplified by Equation VI, toluene may be; alkylated with isobutylene to give 4,6-ditert butyltoluene. The 4,6-di-tert-butyltoluene is then chlorinated, the chlorine going into the open ortho position. The chloro-derivative is then converted by hydrolysis to an hydroxy compound, andthe hydroxy compound is then dealkylatedto give o-cresol. Instead of chlorination in Step 20., I might have sulfonated. In this case, Step 21) would consist of alkali fusion to form the hydroxyl radical. Step 3 would then be 'debutylation. 'An alternate procedure would be to perform a nitration in Step 2a. The nitroradical attached to Step 2a could then be-reduced in Step2b to give the amino derivative; the amino derivative could then be converted to a diazonium salt, and treated with alcohol to form a substituted phenol, which on dealkylation would yield o-cresol.

It is therefore to be understood that in using the term substitution I am referring to a replacement of hydrogen on an aromatic nucleus by an organic or inorganic radical regardless of the number of separate reactions involved in adding a particular radical. I

As mentioned. above if the particular starting out in: a continuous nucleus. Accordingly, this invention is usefully applied to the preparation of substituted aromatic hydroxy compounds such as phenols, naphthols, anthranols: and: other polynuclear' hydroxy compounds. Hydroxylation may be carried out according to conventional systems such as those hereinaboveset forth. In some instances hydroxylation followed .by. dealkylation may be broughtabout by a single operation, such as in high-temperature catalytic hydrolysis of tertiary butylated chlorinated aromatic compounds.

The third major step of my process comprises dealkylating the substituted alkylated hydroxy aromatic compound produced according. to-the preceding steps oLmy invention. This step removes at least one 'of the tertiaryalkyl groups added in step one to produce an hydroxy aromatic compound bearing a substituent in a position on the nucleus other than the position which would be taken on direct, substitution without the aid of a tertiary alkyl blocking agent. As pointed out in the first'major step above, the number of tertiary alkyl groups introduced into the nucleus of the aromatic compound depends? upon the nature of the final product desired; Likewise, in the dealkylation step, the number of tertiary alkyl groups that I split offwill depend upon the final product desired. Dealkylation may be readily effected by heating the substituted alkylated hydroxy aromatic'compound in the 'p'resence' of a dealkylation cataly'sflsuch as-sulfuric acid, alkyl sulfuric acid esters,-;tetra-phosphoric acid, sulfonic acids, activated clays, metal oxides, aluminum chloride,- or the molecular-compounds of aluminum chloride withphenols, alcohols and the like. Inthe case of clays or metal oxides good results have been obtained by contacting the material tobe dealkylated with the heated body of clay or metal-oxide. advantageously conducted at atmospheric pressure, although 'superatmospheric pressures and. sub-atmospheric pressures may be used in some instances. V

It will be understood that in using the term dealkylation I am referring to a splitting off of the oriented tertiary alkyl group or groups added during the first step of my process. lDealkylationf in thecontemplated'manner does not split off such methyl, ethyl, or propyl or other primary or secondary alkyl groups as are present. By the term dealkylation catalysts as used herein, I mean clays and metal oxides or those compounds, usually of an acidrnature, described hereinabove which when present even in relatively small amounts will cause a splittingpfi of the oriented tertiary alkylg-roups added in the first step without substantial decomposition of the original aromatic compound and'withoutafiecting any substituent added in the-second step of my process.

The process of my'invention is commercially attractive-inthati-the tertiary alkyl blocking group may be recovered and used over and over. Thus tertiary olefins, usually of high purity, may be recovered and recycled to the alkylation step. Accordingly, my invntion'may readily be carried manner withwa distinct advantage. -zii'-.-

- Thdrollowingrequations: liaisin -insurm- Dealkylation is cipies'vdf my invention are not to be construed as limiting the same.;-- These equattions'indicate thev essential chemical; reactions which-take/plaQe and do not necessarily indicate all of the actual steps that would be used in preparing and isolating the compounds mentioned. I

- 'E QUATIONI-"' I f4-isdmom'Jl m-Ic resol I 90 13 CaHaV cm smmpylepe) CH:

F C4 s Ha (isobutylene) (Step 2)-Condensation v I I (formaldehyde) (Step 3) Debutylation, V ,s I Li.

I b i -'(3 Inethyl42-hpdroxyphenyl)hiethiine Direct condensetion' of ro-cresol' with formaldehyde would produce a mixture of bis-('3-methy1- 'z-hydroxyphenyl) methane, bis+(3-methy1-4-hy- 8 s droxyphenyl) methane, and 2,4-dihydroxy-3,3'- dimethyl diphenyimethahe.

I EQUATION III I o-Hydrozcybenzoi'c acid (salicylic acid) (Step 1)Butylation 0 I OH I I r I 10 j, +i-ciHa (is butylene) I I t- 4H0.

(Step 2a)Phenate formation I I on ONs I j t- 4Hn 1 I I t 4H; I (Step 2b)Ko1be-Schmitt synthesis 5 I I ONa. 0H

7 COONa CO; -v I t-4H9 II I t- 4H9 V (Step 2c)Acidification I I 1 11 I OH I oo0i a oooH .7 I 1 'L s, t- 4119 t-(hHn Y if (Step 3)Debutylati0n I 1 CI H OH I o I 40 r v -OOOH COOH I t- 4Hs v.

I t I I (isobutylene) t- 4H o-hydroxybenzoie acid Q I (salicylic acid) Nori' n ally the Kolbe-Schmitt synthesis with phe- .nol itself yields a mixture of 0- and p-hydrox'ybenzoic acid.

r EQUATION IV I 2,6-dichlorophenol I (Step 1)Butylation in OH 1-0411; t (isobutylene) s 111w (Step 2)-Ch1orination I OH I *ze-diemtropnenol- 08362 I n AI I I 12 Direct monocvmofinya'tionidrthoxylene would give v. y r I f v;, v a, mixture of 31am: .IrChIQ TO. qrthoxylene leading OH (Step 3 I {:I: I I to the formation ov namfiifml 2,3- and 3,4- I I II II I II I I ylphe oL I HO EQUATION IX allq e (Step 1)Butylatio'1i t-C4H9 catechol 0H 0H Zl- C 4H3 (isobutylene) Direct monochlorinationof phenol would give a mixture of 2- and 4-ch1oropheno1 which upon 4; I hydrolysis would give a, mixture of catechol and (isobutylene) hydroquinone.

" EQUATION x1 o-CresoZ I (ste 1)Butylatiou t -olm" formation of 2,4-dlchlorophenol which upon hy- 4 drolysis would yield a, 1,2,4-trihydroxy benzene.

n; I I I OH EQUATION x 1 v0.11, om -om V +2i-C4Ha I Catechol (isobutylene) (Step 1)-Butylation OH D II I I I I,I OH -C4Ho o-creosol Direct methylation of chlorobenzene would lead to the formation of a mixture of 0- and p-cresol. 2 l-C4Hol I (mbutym?) EQUATION XII t- 4H. o-C'hlorophemol A H (Step 2q)--Chlorination I I (Step 2)-Ch'lorination OH on I 0 OH I eel H. I 01 41.11. 12-0411! 01 t-C4H9 I 66 I t-C4HI III I t- 4H: I 4H t- 4H9 V gstep zpl -Ilydmlysis (Step 3)Debut ylation 113 Direct i-mono chlorination of ;phenol wields i-aemix ture'pf -;,-2 .and-zei-chlorophenol.

Equations I, II, Iv, v, xand anrdliustratel paring .certain specific compounds I according to the process of -.my:invention.

Example =;1 corresponds to the reaction illustrated .hereinabove by Equation .IV.

.Example ,2 corresponds :to .the reaction 1llu s-- trated hereinabove by Equation 1.

- -ExampleB .corresponds {to the reaction jillustratedihereinabove .by Equation .XII.

;2;6+dichlorophenol .Irito .-a -fla'sk provided with an agitator were mascara grams .of phenol and. 4.7. grams of concentratedsulfuric acid. Thephenol-sulfuric acid mixture wasmaintained at a-temperatu-re of 70 C. ,and :isobutylene .-.was introduced slowly below the .surface of the, solution. The addition-of isobutylene to. the reactant mixture wasqcontinued until v5 6;grams ,of .isobutylene had-been"absorbed. The produc'tthus obtained .was washed several timeswithwatenand then refluxed iwithaai-small amount .of..alcoholic;KOH to .neutralize the .remaining acidic bodies. After washing'ag-ain'with water, the neutralized product .was fractionated at atmospheric vpressure through .a .15 .plate column. ,The temperature was-increased-unto 180 C. .during .Whichtime a small amount of polymetizedisobutylene was collected. The "distil- :lationsystem wasthenallowedito cool-and placed under .a..pressure-of 20..mm...of mercury. .Fractionation was then continued whereby there was obtained a small amount of .unreacted phenol boiling .at 85 .C. and a large amountof -4-tertbutylphenolboilingat 130 .to, 13 1 C. at..20 mm. pressure. ".This product had a ,melting 'point of 99C.

136.3 grams 1 of 4-tert-buty1phenol made in accordance with'the aboveprocedure, together'with ZOO-.grams v.of carbon tetrachloride were .placed in a flask excludedfromlight. The carbon; tetrachloridesolution of 4-.tert-.butylphenol:was maintainediat a temperature. of .about C. rand .chlorine was (introduced .below the surface of the solution. .The addition .of chlorine :to the :reactant mixture was continued :until 595.8 ,grams of:ch1orine were, absorbed. The. reaction product was then washed several times .with 5 .per cent aqueous sodium bisulfite to ,remove dissolved chlorine and with per cent aqueous sodium bicarbonate .to remove any hydrogen chloride still present. The product :was then dried with anhydrous sodium-sulfate and charged .to a fractionating-still havingia column equiualenttto .11'5 theoretical :plates. After removing the rcarbon tetrachloride at atmospheric ;,pressure, the aremainder was fractionated into .a-severalrfractions at. a pressure of 20 ;-m of .:.;mercury -;1usin ar mzl-refluxaratio- .Thafractioniho n iatzraoato 152 :10; at; '20 :mm. wasrdetermined to be ;;-2 ,6 -d ichlor-4 tert*butylpheno1. fIhe, z oadichlor 4-tert-butylpheno1obtained-as above ;-was -:theridealkylated by passing it;- in. a molten :state through a Pyr x tube smoked with 15 to .130 --mesh ,Attapulgus clay maintained :at. a temperature between about 275iand 350' C. -;A white: crystalline; material melting-at 64" to 65.5 C. was obtained. Thismaterial-wasdetermined to be 2,6-dichlorophenol.

EXAMPLE 2 4-isopropyl-3-methylphenol Int s sflaskc pr v ded with an a tator-were placed jlfliiegrams :of macresol and 5.4 .srams .of concentrated sulfuric :acid. The; m cresol-sulfuriczacidmi-xture was maintained aha temperature .of {70 C. and ,isobutylene was. introduced SIOWIYabGIOW thG surface ofthe solution. The additionof isobutylene to the :reactant mixture was continued vuntil .56 grams .of isobutylene had been absorbed. The :product thus obtained :was washed several times with 10 .per cent aqueous sodium :hydroxide -and refluxed with a .small amountv of :alcoholic KOH to insure :complete neutralization. of the .acidcatalyst'. The neutralized product was then fractionated .at atmosphericpressurefthrougha 15. plate column. .The temperature. of the column was. increased to.,18.0 C. during ..which.time asmall amount of polymerized isobutylene ,was collected. ..The.distil-. lationsystemwas then allowed to ,cool and ,placed under -.,a pressure of;20. mm. of mercury. F 'rac tionationiwas then continued whereby therewas obtaineda.smallamount of unreacted .m -cresol distilling overiat .10 1-.C. and I a large. amount of gge rigbuty1+3emethylphenol boiling at;129 to 1180.4 grams of 6-tert butylr3:methylphenol made in accordance with the above procedure, together .with 79.0 grams of isopropyl chloride and'iZOO 111.15., ,of carbon ,disulfide were vplaced in a 'Bmeck' flask equipped with a stirrer and a reflux-condenser. While maintaining the ,tem perature of thecontents in the flask at 2'7" -C. 25'6.-.grams of zirconium tetrachloride were added ."in .increments .of 11.65 ,grams' at 510 minute intervals.- .The product obtained by this .reaction was added to ,anice-water mixture and .an oilylayer separated out. "This layer was washed severaltimes with 10 per cent-aqueous sodium bicarbonate tto remove any hydrogen chloride that mightibe present. The product was'then dried-withanhydrous sodium sulfate and charged to 'a fractionating still having a column equivalent to 1'5 theoretical "plates. After removing the carbon disulfide" at atmospheric pressure, the remainder was fractionated into 2 fractions at a pressureof 2O"mm.- of mercury. 'TIhe 'first'iraction boiling between 136.8 and 144.4";0. fiat 201mm. 'wasnmaide 111p -:mainly of pdi-isopropyl-m- I cresols. The :second fraction boiling :between l5l'.2 ;;and A157,.0-tC-..ati-20:;mm. solidification-cooling. L'I'hisr-latter,fractionzwasprecrystallizedrfrom petroleum-ether :until :a. solid "having -a ..constant melting :point was obtained. Thisisolid"'was --a white crystalline :materialwhich .melted sharply at 115;to 116 10. :and-wasidentified as .6- tert-butyl4@isopropyl+3emethylphenoL.

: II1 carrying-gout the :debutylation "step, 220:6

E AMP 3 o-C'lorop enol Into a flask provided with an agitator were placed 100!) grams of phenol and 50 grams of concentratedsulfuric acid. The phenol-sulfuric acid mixture was maintained at atemperature; of 7 0 "C, and isobutylene was'intro'duced slow ly' below the surface of the solution. The addition of isob'utylene was continued until 96]. grams of isobutylene had been absorbed. "The product thus obtained was refluxed with potassidm' "h'yd'roxide' dissolved in absolute alcohol toneutralize the'acid catalyst. The neutralized productwas then washed with water, dried, and fractionated'through aj15 plate columnat atmospheric pressure. Thetemperature of the col-v ume wasjincreased'up to. 190? C; during which time a smallamount of tertiary butyl alcohol, water and polymerized isobutylene were collect-f ed.1:.'1fhe distillation system was then allowed' to cool and placed under a pressure of 20 mm. of mercury. Fractionation was then continued whereby therewas obtainedafsrnall'amount each v of unreacted phenol and of A-tert-butylphenol and. a large amount of 2.4-di-tert-buty1phenol. 103.2 grams of 2,4-di-tert-butylphen'ol made in accordance with the above procedure; together with 300 mls. of carbon tetrachloride were placed in a3-neck flask equipped with a stirrer, a reflux condenser and a thermometer. The carbon tetrachloride solution of 2,4di- -tert-butylphenol was maintained at a temperature between about 3 and 6 C. and chlorinevwas introduced below the surface of the solution. The addition of chlorine to the reactant mixture was continued, until 16.2 grams of chlorine were absorbed. The reaction product was then washed with per. cent aqueous sodium hydroxide and withfwater to remove any hydrogen chloride that might be present. The product wasthen dried with anhydrous. sodium sulfate and charged to a distilling fiask where most of the carbon tetrachloride was removed by heating on a steam bath. After removing the carbon tetrachloride, the remainder of the product was fractionated through the column equivalent to '5 theoretical plates. The'fraction boiling at 148 to 151.2 C. at 20 mm. was determined to be 2,4-di-tert-butyl-6-chlorophenol.

The 2A-di-tert-butyl-G-chlorophenol obtained as above was then dealkylated by contacting it With'fullers earth maintained'at a temperature of about 275 C.- Isobutylene was liberated and i a liquid boiling between 174.5" and 175.8" C. was

collected. "This liquid was determined to consist mainly of o-chlorophenol. There was no evi f dence of'any p'-chlorophenol being formed.

While I have described my inventionherein with respect to various specific examples, it is 'to be understoodthat my invention is'no't limited to '16 the details of such examples, but may be variously practiced and embodied within the scope of the claims hereinafter made.

I claim:- e 1. A'process for producing a substituted hydroxy aromatic'compou'n'd which comprises the ste'ps'of substituting at least one tertiary alkyl matic compound; and thereafter catalytically dealkylating the resulting sub stituted alkylated hydroxy aromatic compound at a dealkylation temperature below about 350 C. to remove at least one tertiary alkyl group introduced by the initial step of the process. 7 r 1 2. A process for producing a substituted phenol which comprises the'steps of substituting at least one tertiary alkyl group having from 4 to 12 carbon atoms on the nucleus of a penhol capable of exerting a directive influence upon the entering tertiary alkyl group; introducing atleast one substituent selected from the group consisting of primary alkyl, secondary alkyl, aryl, aralkyl, afcyl, alkenyl, haloalkyl, hydroxalkyl, alkylamino'alkyl. carboxyalkyl, amino, amido, carbonyl, fiuoro, chlorofbromo, iodo, nitro, sulfo,hydroxy1, mer; capto, cyano, andmercuro radicals'into the,.nu-. cleus of the resulting alkylated phenol; and thereafter catalytically dealkylating the resulting substituted alkylated phenol at a dealkylation'teinperature below about 350?" C. to produce a sub stituted phenol and a free tertiary olefin having from 4 to 12 carbon atoms.

3. A process for producing asubstituted phenol which comprises the steps of substituting at least,

one tertiary butyl'group on the nucleus of a phenol capable of exerting a directive influence upon the entering tertiary butyl group; introducingfat least one substituent selected from the group consisting of primary alkyl, secondary alkyl; aryl, aralkyl; 'acyl, alkenyl, haloalkyl, hydro xy alkyl, alkylaminoalkyh carboxyalkyl, amino. amido, carbonyl, fluoro, chloroi bromo iod o, nitro, sulfoghydroxyl, mercapto, cyano, and mercuro radicals into the nucleus of the resulting alkylatedi phenol; and thereafter catalytically dealkylating the resulting substituted alkylated phenol at a dealkylation temperature below about 350C. to remove at least one tertiary butyl group introducedby the initial step or theprocess.

A process for producing 2, 6-dichlorophenol which comprises alkylating phenol with isobutylene to form 4-tertiary-butylphenol, chlorinating. said -tertiary-butylphenol'to form the corre sponding 2,6gdichloror4-tertiary-butylphenol, and thereafter catalytically @dealkylating said 2,6-dichloro-4 tertiary-butylphenol at a dealkylation temperature below about 350 cto form 2,6-dichlorophenol. Y I 5 Aprocess for producing ortho-chlorophenol which comprises alkyla ting phenol with isobutylene to form '2,4-di-tertiary butylphenol, "ch10 rinating the resulting 2,4-di-tertiaiy butyiphndr to form "the corresponding ZA-di-tertiary-butyl fi-chlorophenol; and thereafter c'atalytically'de alkylating the resulting2,4-di-tertiary-butYl-6 chlorophenol at a dealkylation temperature below about 350 C. to form ortho-chlorophenol.

The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Niederl Mar. 9, 1937 Number 18 Name Date Kyrides June 13, 1939 Driesbach et a1 Mar. 12, 1940 Mills Nov. 19, 1940 Stevens et a1 July 21, 1942 Stevens et a1 Sept. 29, 1942 Olin July 9, 1946 

1. A PROCESS FOR PRODUCING A SUBSTITUTED BYDROXY AROMATIC COMPOUND WHICH COMPRISES THE STEPS OF SUBSTITUTING AT LEAST ONE TERTIARY ALKYL GROUP HAVING FROM 4 TO 12 CARBON ATOMS ON THE NUCLEUS OF AN HYDROXY AROMATIC COMPOUND CAPABLE OF EXERTING A DIRECTIVE INFLUENCE UPON THE ENTERING TERTIARY ALKYL GROUP; INTRODUCING AT LEAST ONE SUBSTITUENT SELECTED FROM THE GROUP CONSISTING OF PRIMARY ALKYL, SECONDARY ALKYL, ARYL, ARALKYL, ACYL, ALKENYL, HALOALKYL, HYDROZYALKYL, AKLYLAMINOALKYL, CARBOXALKYL, AMINO, AMIDO, CARBONYL, FLUORO, CHLORO, BROMO, IODO, NITRO SULFO, HYDROXYL, MERCAPTO, CYANO, AND MERCURO RADICALS INTO THE NUCLEUS OF THE RESULTING ALKYLATED HYDROXY AROMATIC COMPOUND; AND THEREAFTER CATALYTICALLY DEALKYLATING THE RESULTING SUBSTITUTED ALKYLATED HYDROXY AROMATIC COMPOUND AT A DEALKYLATION TEMPERATURE BELOW 350* C. TO REMOVE AT LEAST ONE TERTIARY ALKYL GROUP INTRODUCED BY THE INITAL STEP OF THE PROCESS. 